Debt - Schedule of Debt (Details) - USD ($)	Feb. 28, 2018	May 31, 2017
Total debt	$ 17,611,458	$ 18,032,416
Debt issue costs, net of amortization	(125,634)	(228,426)
Less: Current portion	(8,240,541)	(2,493,236)
Long-term Debt	9,245,283	15,310,754
Term Loan A Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 4.0%, Maturing January 7, 2019 [Member]
Total debt	4,116,415	4,626,191
Term Loan B Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 4.0% [Member]
Total debt		1,715,132
Term Loan C Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.0%, Maturing August 4, 2020 [Member]
Total debt	1,667,182
Term Loan D Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.75%, Maturing January 10, 2022 [Member]
Total debt	2,452,757
Term Loan E Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.75%, Maturing January 10, 2022 [Member]
Total debt	525,200
Revolving Loan Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.75%, Due January 31, 2020 [Member]
Total debt		2,260,000
Note Payable to First Bank, Prime Rate of Interest Plus 1.45% but Not Less Than 4.95%, Monthly Principal and Interest Payment of $30,628, Due August 21, 2021, Secured by Production Equipment [Member]
Total debt	1,176,233	1,396,448
Term Loan Payable by Gre to International Bank of Commerce, Interest Rate of 4.5%, Monthly Principal and Interest Payment of $26,215, Due January 31, 2019 [Member]
Total debt	2,700,205	2,841,285
Note Payable to Robert Rosene, 7.5% Interest, Due January 15, 2020 [Member]
Total debt	4,469,355	4,469,355
Note Payable to Yorktown Management & Financial Services, LLC, 5.0% Interest, Due February 28, 2019, Monthly Principal and Interest Payments of $20,629 [Member]
Total debt	240,970	413,969
Other Note Payable [Member]
Total debt	$ 263,141	$ 310,036